java 输入输出小总结

1.获取键盘输入

public class MyConsole {private static Scanner sc;public  static String inputFromConsole(){String input = null;BufferedReader br1;try {br1 = new BufferedReader(new InputStreamReader(System.in,"UTF-8"));input=br1.readLine();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}return input;}}

2.从文件中读取

File f = new File(tableAddress);BufferedReader br = new BufferedReader(new FileReader(f));String line;while ((line = br.readLine()) != null) {System.out.println(line);}br1.close();

3.从文件中删除

//方法：生成一个临时文件，读出，把需要的读入，删除的不读，最后，把原来文件删掉，把临时文件rename成原文件的名字File f = new File(tableAddress);FileReader fr = new FileReader(f);BufferedReader br = new BufferedReader(fr);File tempFile = new File(tableAddress + ".tmp");PrintWriter pw = new PrintWriter(new FileWriter(tempFile));String str = null;str = br.readLine();while (str != null) {String split[] = str.split(" ");if (!split[0].equals(index)) {pw.println(str);pw.flush();}split = null;str = br.readLine();}pw.close();br.close();fr.close();// FileWriter fw = new FileWriter(f, false);// BufferedWriter bw = new BufferedWriter(fw);// bw.write(newFile);// bw.close();// fw.close();f.delete();tempFile.renameTo(f);}

4.从文件中修改

//如果不包含要修改的信息，直接添加到newFile，包含则修改后添加，最后把newFile读回，注意，append要设为false

FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
String str = null;
str = br.readLine();


int count = 0;
String newFile = "";


while (str != null) {
if (!str.contains("admin")) {
if (count == 0)
newFile += str;
else
newFile += "\r\n" + str;
} else
newFile += "admin" + " " + password;
count++;
str = br.readLine();
}
br.close();
fr.close();
FileWriter fw = new FileWriter(f, false);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(newFile);
bw.close();
fw.close();